Leaf dew contributes nutrients to paddies and improves rice growth.

摘要

Leaf dew is an important input in farmland ecosystems, but information regarding the nutrients from leaf dew deposition in paddy fields is scarce. Leaf dew samples were monitored and collected in situ from the Sanjiang Plain paddy experimental station during the rice growing periods in 2008, 2009, and 2010. The pH and essential nutrients [ammonium nitrogen (NH₄+-N), nitrate nitrogen (NO₃--N), and phosphorus (P)] in paddy leaf dew were investigated, the nutrients in guttation and condensed dew were distinguished. In addition, the nutrient contributions of foliar fertilizer to Oryza sativa L (rice) were compared with those of leaf dew. The results indicate that the mean pH of leaf dew on rice is 6.3 (n=56), lower than the pH of rain and surface water. Condensed dew contributes about 97.7% of the nitrogen (N) and 95.7% of the phosphorus (P) in paddy leaf dew. Guttation provides a minor part of the N and P in leaf dew. The amount of leaf dewfall is much larger than the volume of foliar fertilization, with the amount of NH₄--N, NO₃--N,, and P deposition from leaf dew almost 100 higher than from foliar fertilization. Compared with foliar fertilizer, leaf dew is a natural and potential fertilizer. Leaf dew is an important pathway for nutrient transfer within paddies.